JP5283584B2 - Progressive power lens - Google Patents

Description

The present invention, one surface is a progressive surface, about the progressive power lens in which the other surface is an aspherical or non-toroidal surface.

  Progressive power lenses have been developed in which the refractive power continuously changes from a portion having a refractive power for far vision to a portion having a refractive power for near vision. This progressive-power lens is mainly used as a presbyopic eyeglass lens, and it is difficult to distinguish from presbyopia in appearance, and has the advantage that it can be continuously clearly visible from a distance to the hand. It's being used.

  As for the surface configuration of the progressive power lens, a progressive surface is arranged on the object side surface (front surface) and a spherical surface or toroidal surface (astigmatism surface) is arranged on the eyeball side surface (rear surface). There is known a spherical surface on the side surface (front surface) and a progressive surface or a composite surface of a progressive surface and a toroidal surface on the eyeball side surface (rear surface). In addition, in order to perform aberration correction (for example, correction of astigmatism, curvature of field, distortion, etc.) according to the prescription power in a region on the lens peripheral side, the spherical surface or toroidal surface constituting the one surface is aspherical. Or the thing comprised by the non-toroidal surface is proposed (for example, refer patent documents 1 and 2).

In the present specification, a curved surface which is a part of a rotating surface having one rotating shaft and whose curvature continuously changes from the intersection with the rotating shaft to the periphery is referred to as an aspheric surface. Further, the main meridian indicating the maximum curvature and the main meridian indicating the minimum curvature are part of a line-symmetric curved surface with the normal line at the intersection as a symmetry axis, and at least one main meridian is the other main meridian A curved surface whose curvature continuously changes from the intersection with the meridian to both outer sides is called a non-toroidal surface. A progressive-power lens in which a progressive surface is arranged only on one surface is also referred to as a single-sided progressive-power lens. Further, the surface opposite to the progressive surface of the single-sided progressive-power lens, a surface made of a spherical surface or a toroidal surface is also called a spherical design surface, and a surface made of an aspherical surface or a non-toroidal surface is also called an aspherical design surface. . In addition, the surface opposite to the progressive surface of this single-sided progressive-power lens is made up of a spherical design surface, also called a spherical design single-sided progressive-power lens, and an aspheric design surface made up of an aspheric design surface. It is also called a single-sided progressive power lens.
In this aspherical design single-sided progressive addition lens, aberrations on the lens peripheral side are corrected, so that optical characteristics acting on the eye are improved and the lens can be made thin.

Japanese translation of Japanese translation of PCT publication No. 07-504769 JP-A-57-10112

The values indicating the optical performance of the progressive power lens include the distance power (rear apex power, hereinafter also referred to as “distance power”), the astigmatism axis direction, and the addition power (usually the progressive surface lens) The difference between the average refractive power of the near portion and the average refractive power of the near portion measured against the lens contact of the meter (hereinafter also referred to as addition power), prism refractive power (hereinafter also referred to as prism power), prism base direction, etc. Each lens has these lens design values displayed on the lens package, attached document, lens, etc. (hereinafter, these optical performances displayed on the lenses are also referred to as display values). ).
The tolerances for these optical performance measurement methods and the measured optical performance values displayed are determined by Japanese Industrial Standards (for example, JIS T7331, JIS T7315) and international standards (for example, ISO14889, ISO8980-2).
In this specification, the term “prism refractive power” means only one of the prescription prism refractive power and the prism thinning when it has only one of the prescription prism refractive power and the prism thinning. Means the prism refractive power obtained by combining them.

  Whether the lens has the optical performance according to the display value given to the lens on the side that sells spectacle lenses or spectacles (for example, a spectacle store, an ophthalmologist, a lens manufacturer, a lens manufacturer's custom-made factory, etc.) It is necessary to measure the optical performance of the lens in order to check whether the lens has optical performance that matches the wearer's prescription. Such measurement of optical performance is performed using a lens meter or a measurement device capable of obtaining a measurement value equivalent to the measurement method according to the measurement method defined by JIS or ISO or a measurement method based thereon.

By the way, when the progressive-power lens is an aspherical design single-sided progressive-power lens, the refractive power actually acting on the eye at the wearing position is measured with a lens meter because of the aspherical design on one side. The refractive power may be different. For this reason, in the aspherical design single-sided progressive addition lens, the prescribed distance power and addition power (hereinafter also referred to as prescription power), and the distance power and addition power to be measured are measured. (Hereinafter, these are also referred to as check frequencies) are described on the package of the lens and attached documents.
In this way, in the aspherical design single-sided progressive addition lens, since there is a prescription power and a check power in one lens, the lens according to the prescription of the wearer or when inspecting the lens on the sales side described above There was a possibility of causing confusion when selecting.

  In view of the above problems, the present invention is capable of performing aberration correction according to the prescription power and measuring it in a progressive power lens in which one surface is a progressive surface and the other surface is an aspheric design surface. It is an object of the present invention to design a lens shape so that the distance portion refractive power and the addition refractive power substantially coincide with the prescription power.

In order to solve the above-mentioned problems, the present invention is a progressive power lens having a progressive surface and an aspheric design surface made up of an aspheric surface or a non-toroidal surface, and the reference point of the aspheric design surface is the upper and lower surfaces of the lens. In the direction, the position is a position below the prism measurement reference point on the progressive surface and a position above the near-field design reference point. The difference in surface refractive power at the position on the aspheric design surface corresponding to the distance measurement reference point of the progressive surface with respect to the surface refractive power at the reference point of the aspheric design surface and the surface at the reference point of the aspheric design surface the difference between the surface refractive power at a position on the aspherical surface design surface corresponding to the near design reference point of the progressive surface to the refractive power is designed to equal made properly.

As described above, the progressive-power lens according to the present invention has a progressive surface and an aspheric design surface composed of an aspherical surface or a non-toroidal surface, and the reference point of the aspherical design surface is progressively advanced in the vertical direction of the lens. It is configured as a position below the prism measurement reference point of the surface and as a position above the near part design reference point.
In a conventional progressive-power lens, when one surface is an aspheric design surface composed of an aspheric surface or a non-toroidal surface, the aspheric design surface reference point (aspheric reference point or non-toroidal surface reference point) is a progressive surface. The surface refractive power in a predetermined direction of the rear surface of the lens in a vertical section passing through the prism measurement reference point is the position of the lens front surface (progressive surface) at the prism measurement reference point. The distribution is symmetric with the line as the central axis. On the other hand, the distance between the distance measurement reference point and the prism measurement reference point, and the distance between the near design reference point and the prism measurement reference point are usually not equal. The interval is slightly longer. Therefore, the surface refractive power of the rear surface at the rear surface corresponding point of the distance measurement reference point and the rear surface corresponding point of the near portion design reference point are different, and this is the addition refractive power measured by the lens meter. And the addition power in the prescription power are different.

  On the other hand, as described above, in the progressive-power lens of the present invention, the reference point of the aspherical design surface is shifted downward from the prism measurement reference point and above the near-part design reference point. Because of the position, it is possible to reduce the difference in surface refractive power between the rear surfaces of the rear surface corresponding point of the distance measurement reference point and the rear surface corresponding point of the near portion design reference point. Thereby, it becomes possible to eliminate the difference between the addition refractive power measured by the lens meter derived from providing the aspheric design surface and the addition refractive power at the prescription power.

  According to the present invention, in a progressive-power lens having a progressive surface and an aspheric design surface composed of an aspherical surface or a non-toroidal surface, aberration correction corresponding to the prescription power is performed particularly in the lens peripheral side region. At the same time, it is possible to obtain a lens in which the measured distance power and addition power are substantially equal to the prescribed distance power and addition power. Thereby, it is not necessary to separately display the check frequency on the lens, and the optical performance of the lens can be easily inspected.

A and B are a plan view and a cross-sectional view as seen from the front side (opposite side to the eyeball side) of an aspherical design single-sided progressive addition lens (for the left eye) according to an embodiment of the present invention. It is a figure which shows the power change of the rear surface in the conventional progressive power lens which makes a rear surface an aspherical surface or a non-toroidal surface. It is a figure which shows the frequency change of the rear surface in the state which shifted the rear surface of the progressive-power lens shown in FIG. 2 on the y-axis downward. It is a figure which shows the power change of the rear surface after deform | transforming the lens rear surface so that the amount of power changes of the rear surface in the distance measurement reference point in the progressive power lens shown in FIG. 3 may be subtracted from the lens rear surface. FIGS. 8A to 8C are diagrams illustrating a step of correcting in consideration of the prism refractive power in the shape data creation method of the aspherical design single-sided progressive-power lens according to the embodiment of the present invention. FIG. 6 is a distribution in a progressive-power lens according to an embodiment in which a front surface (convex surface) is a progressive surface and a rear surface (concave surface) is an aspheric surface, and A to C are distributions of surface astigmatism, surface average power, and height on the progressive surface. D to F show surface astigmatism, surface average power, and height distribution on the aspheric surface, and G and H are diagrams showing astigmatism and power error in the power on the reference spherical surface. FIG. 4 is a distribution in a progressive-power lens according to an embodiment in which a front surface (convex surface) is a progressive surface and a rear surface (concave surface) is a non-toroidal surface, and A to C are distributions of surface astigmatism, surface average power, and height on the progressive surface. D to F show surface astigmatism, surface average power, and height distribution on the non-toroidal surface, and G and H show astigmatism and power error in the power on the reference spherical surface. A and B are diagrams showing astigmatism and power error of target performance (transmittance number on a reference spherical surface). It is a part of flowchart for demonstrating the procedure of the shape data creation method of the progressive-power lens which concerns on the embodiment of this invention. It is a part of flowchart for demonstrating the procedure of the shape data creation method of the progressive-power lens which concerns on the embodiment of this invention. It is a part of flowchart for demonstrating the procedure of the shape data creation method of the progressive-power lens which concerns on the embodiment of this invention. It is a block block diagram which shows the shape data creation apparatus of the progressive-power lens which concerns on the embodiment of this invention. A and B are a plan view and a cross-sectional view as viewed from the front side (the side opposite to the eyeball side) of a conventional aspherical design single-sided progressive addition lens (for the left eye). A and B are diagrams showing the surface astigmatism of the rear surface of the progressive-power lens having the rear surface as a non-toroidal surface and the power change of the rear surface on the y-axis. A and B are a plan view and a cross-sectional view of a conventional spherically designed single-sided progressive power lens (for the left eye) as viewed from the front side (the side opposite to the eyeball side). FIGS. 7A and 7B are diagrams showing surface astigmatism on the rear surface of a progressive-power lens having a rear surface as a toroidal surface and the power change of the rear surface on the y axis. FIGS. This is a distribution in a progressive-power lens according to a comparative example in which the front surface (convex surface) is a progressive surface and the rear surface (concave surface) is a spherical surface. A to C are surface astigmatism, surface average power, and height distributions on the progressive surface. , D to F show surface astigmatism, surface average power, and height distribution on the spherical surface, and G and H are diagrams showing astigmatism and power error in the power on the reference spherical surface. It is a distribution in a progressive power lens according to a comparative example in which a front surface (convex surface) is a progressive surface and a rear surface (concave surface) is a toroidal surface, and A to C are surface astigmatism, surface average power, and height distributions on the progressive surface. D to F show surface astigmatism, surface average power, and height distribution on the toroidal surface, and G and H show astigmatism and power error in the power on the reference spherical surface.

Examples of the best mode for carrying out the present invention will be described below, but the present invention is not limited to the following examples.
First, referring to the drawings, an aspherical design single-sided progressive-power lens according to an embodiment of the present invention, and a conventional aspherical design single-sided progressive-power lens and a spherical-designed single-sided progressive-power lens as a comparison target will be described with reference to the drawings. explain.

FIG. 1 is a diagram showing an example of an aspherical design single-sided progressive addition lens 10 for a left eye in which a progressive surface is arranged on the front surface according to the present invention, and FIG. 1A is a front surface 1 side (the eyeball side) of the lens 10. FIG. 1B shows a cross-sectional configuration diagram viewed from the opposite side.
The lens 10 shown in FIGS. 1A and 1B is a meniscus lens, the lens front surface (object-side surface) 1 is a progressive surface having a generally convex shape, and the lens rear surface (eyeball-side surface) 2 is concave. It consists of an aspherical surface or a non-toroidal surface. A prism measurement reference point P3 is arranged at the center of the lens on the lens front surface 1. The distance measurement reference point P1 is on the lens front surface 1 above the prism measurement reference point P3 and the lens measurement reference point P1 is near on the lens front surface 1 below. A partial design reference point P2 is arranged.

The prism measurement reference point P3 is the origin, the normal of the lens front surface 1 at the prism measurement reference point P3 is the Z axis, the horizontal direction of the lens passing through the prism measurement reference point P3 and perpendicular to the Z axis is the X axis, and the prism measurement reference point P3 In the three-dimensional Cartesian coordinate system in which the vertical direction of the lens perpendicular to the Z-axis passes through the Y-axis, the near-field design reference point P2 is normally the nose side (glasses in the X-axis direction from the Y-axis when viewed from the front of the lens The distance in the Y-axis direction (distance from the XZ plane) from the prism measurement reference point P3 viewed from the front of the lens is farther from the near-field design reference point P2. It is set longer than the use part measurement reference point P1.
Further, in the example shown in FIG. 1, the front-view external shape of the lens 10 is circular, and the prism measurement reference point P3 is located at the center of the circular shape, and the distance measurement reference point P1 is the lens. It is located on the Y axis when viewed from the front.
The positions of the distance measurement reference point P1, the near vision design reference point P2, and the prism measurement reference point P3 are uniquely set by the lens manufacturer according to the optical design of the lens. These points can be determined with reference to a permanent alignment reference mark (not shown) provided on the front surface 1 of the lens.

  FIG. 1B is a cross-sectional view of the lens 10 in the YZ plane, and shows the corresponding point P1 ′ on the rear surface 2 of the distance measurement reference point P1 set on the lens front surface 1 and the near design reference point P2. A corresponding point P2 ′ on the rear surface 2 and a corresponding point P3 ′ on the rear surface 2 of the prism measurement reference point P3 are shown.

Here, the corresponding point P1 'on the rear surface of the distance measurement reference point is the intersection of the normal line at the distance measurement reference point P1 on the lens front surface 1 and the lens rear surface 2, and is a progressive surface when measuring the addition power. This corresponds to the point where the lens meter optical axis and the lens rear surface 2 intersect when the optical axis of the lens meter and the distance measurement reference point P1 are matched while the front surface 1 is in contact with the lens contact of the lens meter.
Also, the near-point design reference point rear surface corresponding point P2 ′ is the intersection of the normal at the near-point design reference point P2 of the lens front surface 1 and the lens rear surface 2, and is the progressive surface when measuring the addition power. This corresponds to a point where the lens meter optical axis and the lens rear surface 2 intersect when the optical axis of the lens meter and the near portion design reference point P2 are matched while 1 is applied to the lens contact of the lens meter.
A corresponding point P3 ′ on the rear surface of the prism measurement reference point is an intersection of the normal line (Z axis) at the prism measurement reference point P3 on the lens front surface 1 and the rear surface 2 of the lens.

In the lens 10 according to the present embodiment, as shown in FIG. 1B, a reference point (aspheric reference point or non-toroidal reference point) of the aspheric design surface (aspherical surface or non-toroidal surface) which is the rear surface 2 of the lens. ) Ph is below the prism measurement reference point P3 in the Y-axis direction (below the XZ plane) when viewed from the front of the lens 10, and above the near-part design reference point P2 in the Y-axis direction (nearly) It is set at a position above the plane parallel to the XZ plane passing through the part design reference point P2. More preferably, the aspheric design surface reference point Ph is lower in the Y-axis direction (below the XZ plane) than the corresponding point P3 ′ on the rear surface of the prism measurement reference point when viewed from the front of the lens, and the near portion design. This is a position above the reference point rear surface corresponding point P2 ′ in the Y-axis direction (above a plane parallel to the XZ plane passing through the near part design reference point rear surface corresponding point P2 ′).
Here, in the present specification, the aspheric design surface reference point is an intersection of the rotation axis and the lens rear surface 2 when the aspheric design surface is an aspheric surface, and the two principal meridians when the aspheric design surface is an aspheric surface. Is the intersection of The aspheric rotation axis is referred to as an aspheric reference axis, the normal at the intersection of two principal meridians of the non-toroidal surface is referred to as a non-toroidal surface reference axis, and these are referred to as an aspheric design surface reference axis.

The aspheric design surface reference point Ph is preferably set on the Y axis (on the YZ plane) when viewed from the front of the lens 10, and the distance measurement reference point P1 and the near design reference point P2 when viewed from the front of the lens. Is more preferably set on the line connecting the distance measurement reference point P1 and the distance design reference point P2 (on the plane parallel to the Z axis). The aspherical design surface reference point Ph is set in the region closer to the nose than the Y axis and closer to the ear than the line connecting the distance measurement reference point P1 and the near design reference point P2 when viewed from the front of the lens. May be.
Also, the refractive power of the rear surface of the lens at the corresponding point P1 ′ on the rear surface of the distance measurement reference point and the refractive power of the rear surface of the lens at the corresponding point P2 ′ on the rear surface of the near reference design point are designed to be substantially the same. Has been.
By configuring in this way, the addition power measured by the lens meter as the optical performance value of the lens can substantially coincide with the addition power as the prescription power or be within a predetermined tolerance.
Further, it is more preferable that the aspheric design surface reference axis is inclined downward toward the lens front surface side. With this configuration, the prism refractive power can be easily set within an allowable range.

The corresponding point P1 ′ on the rear surface of the distance measurement reference point may be the position of the intersection of the normal of the lens rear surface 2 passing through the distance measurement reference point P1 and the lens rear surface 2. Further, the corresponding point P1 ′ on the rear surface of the distance measurement reference point is set to the position of the intersection of the line parallel to the Z axis passing through the distance measurement reference point P1 and the lens rear surface 2, or the rear surface of the near design reference point The design may be simplified by setting the upper corresponding point P2 ′ as the position of the intersection of a line parallel to the Z axis passing through the near portion design reference point P2 and the lens rear surface 2.
The material of the lens 10 according to the present invention is not particularly limited, and can be, for example, a conventional plastic or glass spectacle lens.

FIG. 13 is a diagram showing an example of a conventional aspherical design single-sided progressive-power lens 20 for the left eye in which a progressive surface is arranged on the front surface of the related art, and FIG. 13A is a plan view of the lens 20 viewed from the front surface 21 side. FIG. 13B shows a cross-sectional configuration diagram thereof.
In the lens 20 shown in FIGS. 13A and 13B, the lens front surface 21 is a progressive surface, and the lens rear surface 22 is an aspherical surface or a non-toroidal surface. The lens front surface 21 has its surface shape, position and orientation in a three-dimensional orthogonal coordinate system, and each point on the lens front surface 21 (distance portion measurement reference point P1, near portion design reference point P2, prism measurement reference). Since the position of the point P3) is the same as that of the lens front surface 1 of the lens 10 according to the present invention shown in FIG.

  FIG. 13B is a cross-sectional view of the lens 20 in the YZ plane, and shows a corresponding point P1 ″ on the rear surface 22 of the distance portion measurement reference point P1 set on the lens front surface 21, and a near portion design reference point P2. A corresponding point P2 ″ on the rear surface 22 and a corresponding point P3 ″ on the rear surface 22 of the prism measurement reference point P3 are shown.

  Here, the corresponding point P1 ″ on the rear surface of the distance measurement reference point is an intersection of the normal of the lens front surface 21 and the lens rear surface 22 at the distance measurement reference point P1, and is on the rear surface of the near vision design reference point. The corresponding point P2 ″ is an intersection of the normal of the lens front surface 21 and the lens rear surface 22 at the near portion design reference point P2, and the corresponding point P3 ″ on the rear surface of the prism measurement reference point is at the prism measurement reference point P3. This is the intersection of the normal line (Z axis) of the lens front surface 21 and the lens rear surface 22.

  As shown in FIG. 13B, the reference point Ph2 of the aspheric design surface, which is the lens rear surface 22, is set at the same position as the prism measurement reference point P3 when viewed from the front of the lens 20. That is, the aspheric design surface reference point Ph2 coincides with the position of the corresponding point P3 '' on the rear surface of the prism measurement reference point. The aspheric design surface reference axis is set in a direction in which a desired prism refractive power can be obtained, and coincides with the Z axis when the prism refractive power is zero.

FIG. 15 is a diagram showing an example of a conventional spherically-designed progressive-power lens 30 for a left eye in which a progressive surface is arranged on the front surface, and FIG. 15A is a plan view showing the lens 30 viewed from the front surface 31 side. FIG. 15B shows a cross-sectional configuration diagram thereof.
15A and 15B, the lens front surface 31 is a progressive surface, and the lens rear surface 32 is a spherical surface or a toroidal surface. The lens front surface 31 has a surface shape, a position and orientation in a three-dimensional orthogonal coordinate system, and points on the lens front surface 31 (distance portion measurement reference point P1, near portion design reference point P2, prism measurement reference). Since the position of the point P3) is the same as that of the lens front surface 1 of the lens 10 according to the present invention shown in FIG.

FIG. 15B is a cross-sectional view of the lens 30 in the YZ plane. The corresponding point P1 ′ ″ on the rear surface 32 set on the lens front surface 31 and the near portion design reference point P2 are set on the rear surface 32. A corresponding point P2 ′ ″ on the rear surface 32 and a corresponding point P3 ′ ″ on the rear surface 32 of the prism measurement reference point P3 are shown.
Here, the corresponding point P1 ′ ″ on the rear surface of the distance measurement reference point is an intersection of the normal of the lens front surface 31 and the lens rear surface 32 at the distance measurement reference point P1, and the rear surface of the near design reference point. The upper corresponding point P2 ′ ″ is the intersection of the normal of the lens front surface 31 and the lens rear surface 32 at the near portion design reference point P2, and the prism measurement reference point rear upper corresponding point P3 ′ ″ is the prism measurement reference. This is the intersection of the normal line (Z axis) of the lens front surface 31 and the lens rear surface 32 at the point P3.

When the lens rear surface 32 is a toroidal surface, the toroidal surface reference point Ph3 is set at the same position as the prism measurement reference point P3 when viewed from the front of the lens 30, as shown in FIG. 15B. That is, the toroidal surface reference point Ph3 coincides with the position of the corresponding point P3 ′ ″ on the rear surface of the prism measurement reference point.
Here, in this specification, the toroidal surface reference point is an intersection of two principal meridians of the toroidal surface. The normal line of the toroidal surface at this intersection is called the toroidal surface reference axis. The toroidal surface reference axis is set in a direction in which a desired prism refractive power can be obtained. When the prism refractive power is zero, it coincides with the Z axis. When the lens rear surface 32 is a spherical surface, a straight line connecting the center of the sphere including the spherical surface and the corresponding point P3 ′ ″ on the rear surface of the prism measurement reference point is set in a direction in which a desired prism refractive power can be obtained. When the refractive power of the prism is 0, it coincides with the Z axis.

Next, the refractive power of the aspherical design surface of the conventional aspherical design single-sided progressive power lens 20 and the spherical design surface of the spherically designed single-sided progressive power lens 30 will be described with reference to the drawings.
The conventional aspherical design single-sided progressive power lens 20 described here has a progressive surface on the front surface and a non-toroidal surface on the rear surface of the lens. The conventional spherically designed single-sided progressive power lens 30 has a progressive surface on the front surface and the rear surface of the lens. Consists of a toroidal surface. The prescription powers of these lenses 20 and 30 are such that the distance power is 6.00D for spherical power (also called spherical power), -3.00D for astigmatic power (also called astigmatic power) -3.00D, and the astigmatic axis is 0 °. And the addition refractive power is 2.00 D. The prism refractive power is 0.00Δ. The front lens curve is 7.00D, and the rear lens curve is 4.19D at the maximum and 1.19D at the minimum (however, in the case of a progressive surface or an aspheric design surface, the surface refractive power varies depending on the position). doing). The refractive index of the lens material is 1.60, and the center thickness is 6 mm.

  FIG. 14A is a diagram showing the distribution of surface astigmatism of the lens rear surface 22 of the conventional aspherical design single-sided progressive power lens 20 on the xy plane, and FIG. 16A is the conventional spherically designed single-sided progressive refractive power. It is the figure which showed distribution of the surface astigmatism of the lens rear surface 32 of the force lens 30 on the xy plane.

  Here, in FIGS. 14A and 16A, and FIGS. 6D to F, FIGS. 7D to F, FIGS. 17D to F, and FIGS. 18D to F, which will be described later, ”, P3 ″, P3 ′ ″) and the normal line (2, 22, 32) of the lens rear surface (2, 22, 32) at the corresponding point (P3 ′, P3 ″, P3 ′ ″) on the rear surface of the prism measurement reference point. It is a two-dimensional orthogonal coordinate consisting of a plane perpendicular to the z-axis). The position of the corresponding point (P3 ', P3' ', P3' ') on the rear surface of the prism measurement reference point is the origin, the horizontal direction of the lens is the x axis, and the vertical direction of the lens is the y axis.

  FIG. 14B is a diagram showing the amount of change in the surface refractive power in the y-axis direction of the rear surface of the lens on the yz plane of the conventional aspherical design single-sided progressive addition lens 20, and FIG. 16B shows the conventional spherical surface. It is the figure which showed the variation | change_quantity of the surface refractive power of the lens back surface y-axis direction on the yz plane of the design single-sided progressive-power lens 30. FIG.

  Here, in FIGS. 14B and 16B and FIGS. 2, 3 and 4 to be described later, the positions of the corresponding points (P3 ′, P3 ″, P3 ′ ″) on the rear surface of the prism measurement reference point on the y-axis. Yp from the corresponding points (P3, P3 ″, P3 ′ ″) on the rear surface of the prism measurement reference point of the distance measurement point on the rear surface (P1 ′, P1 ″, P1 ′ ″) The distance in the axial direction is yd, the corresponding point on the rear surface of the near reference design reference point (P2 ′, P2 ″, P2 ′ ″), the corresponding point on the rear surface of the prism measurement reference point (P3 ′, P3 ″, P3 ″) The distance in the y-axis direction from ') is indicated as yn. Further, the amount of change in surface refractive power is the corresponding point on the rear surface of the prism measurement reference point (P3 ′, P3 ″, P3 ′ ″) from the surface refractive power in the y-axis direction of the lens rear surface at each position on the y-axis. The value obtained by subtracting the surface refractive power in the y-axis direction of the lens rear surface at.

  In the example of the conventional spherically designed single-sided progressive addition lens 30 shown in FIG. 15, the surface astigmatism of the lens rear surface 32 is the same value (−3.00D) over the entire area as shown in FIG. 16A. As shown in FIG. 16B, the amount of change in the surface refractive power in the y-axis direction on the rear surface of the lens on the yz plane is constant over the entire area on the y-axis. That is, the rear surface y-axis direction surface power change amount DD at yd on the y-axis and the rear surface y-axis direction surface power change amount DN at yn are both zero. Therefore, in this example, the measured distance power and addition power almost coincide with the prescription power.

  On the other hand, in the case of the conventional aspherical design single-sided progressive addition lens 20 shown in FIG. 13, the surface astigmatism of the lens rear surface 22 increases as it goes to the lens peripheral side as shown in FIG. 14A. Distribution is generated so that the value becomes smaller. Further, as shown in FIG. 14B, the amount of change in the surface refractive power in the y-axis direction of the rear surface of the lens on the yz plane is the smallest in yp, and becomes symmetrically larger as the distance from yp in the vertical direction on the y-axis is increased. Yes. It can be seen that the rear surface y-axis direction surface power change amount DD in yd on the y-axis and the rear surface y-axis direction surface power change amount DN in yn have different values.

  Thus, in the conventional aspherical design single-sided progressive power lens, the amount of change in surface refractive power of the aspherical design surface at the corresponding point P1 ″ on the rear surface of the distance measurement reference point and the rear surface of the near design reference point The difference between the surface refractive power change amount of the aspheric design surface at the upper corresponding point P2 ″ is one of the factors that cause the measured addition power and distance portion refractive power to differ from the prescription power. For this reason, in the conventional aspherical design progressive-power lens, it is necessary to separately add a check power to the lens as a display value.

Therefore, in this embodiment, the position of the aspheric design surface reference point is moved downward in the Y-axis direction, and the surface refractive power and the near use at the point on the aspheric design surface corresponding to the distance measurement reference point are measured. The difference from the surface refracting power at the point on the aspheric design surface corresponding to the partial design reference point is made smaller, preferably about the same value.
The concept of the lens designing method according to the present invention will be described with reference to FIGS. 2 to 4 in the case of the aspherical design single-sided progressive addition lens according to the present invention shown in FIG. The aspherical design single-sided progressive-power lens according to the present invention described here comprises a progressive surface on the front surface of the lens and an aspheric design surface on the rear surface of the lens.

2 to 4 are diagrams sequentially illustrating the amount of change in the surface refractive power in the y-axis direction of the rear surface of the lens on the yz plane in each process of designing the aspherical design single-sided progressive power lens 10 according to the present invention. is there.
FIG. 2 shows a prism measurement standard of the lens front surface 1 which is a progressive surface before the lens rear surface 2 is moved downward relative to the lens front surface 1 to move the position of the aspherical design surface reference point Ph downward. A change amount of the surface refractive power in the y-axis direction of the lens rear surface on the yz plane in a state where the aspheric design surface reference point Ph of the lens rear surface 2 is located on the normal line at the point P3 is shown. Since FIG. 2 is the same as FIG. 14B, description thereof is omitted. As described above, in FIG. 2, the rear surface y-axis direction surface power change amount DD at yd on the y-axis and the rear surface y-axis direction surface power change amount DN at yn have different values.

  Next, FIG. 3 shows the state after the lens rear surface 2 is moved downward relative to the lens front surface 1 to move the position of the aspheric design surface reference point Ph downward. The change amount of the surface refractive power in the y-axis direction of the lens rear surface is shown. That is, in the state of FIG. 2, the rear lens surface 2 is translated in the y-axis direction until the rear surface y-axis direction surface power change amount DD in yd and the rear surface y-axis direction surface power change amount DN in yn coincide. The state after making it show is shown. In this example, DD = DN when shifted by ΔY. In this state after the movement, the aspheric design surface reference point Ph is located vertically below the prism measurement reference point P3 when viewed from the front of the lens. By moving the lens rear surface 2 relative to the lens front surface 1 in this way, the value of the surface refractive power change amount in the y-axis direction of the lens rear surface 2 is also slid downward in the y-axis direction from the value in FIG. It has become the value. And DD = DN. However, the values of DD and DN are not 0 at this time.

Next, FIG. 4 shows the amount of change in the surface refractive power in the y-axis direction of the lens rear surface on the yz plane after the shape of the lens rear surface 2 is deformed. That is, a state after the shape of the lens rear surface 2 is deformed so that the surface refractive power of the entire lens rear surface 2 is subtracted by ΔD so that DD and DN are each 0 is shown.
As a result, DD and DN are 0, that is, the distance measurement power at the distance measurement reference point P1 'and the near distance measurement reference point at the back surface corresponding point P3' of the prism measurement reference point before the rear surface movement. The surface refractive power of the corresponding point P2 ′ on the rear surface is almost in agreement. As a result, the influence of DD and DN at the time of refractive power measurement is eliminated, so that the measured values of the distance power and the addition power can be matched with the prescription power.

In the above description, since the prism refractive power, the lens center thickness, and the like are not considered, a design method that takes these into consideration will be described with reference to FIGS. In this description, as in the case of the aspherical design single-sided progressive addition lens 10 in which the lens front surface 1 is a progressive surface and the lens rear surface 2 is an aspheric design surface in the same manner as described above, the prism refractive power is 0.00Δ. explain.
FIG. 5 is a diagram sequentially showing cross-sectional views in the YZ plane of the lens 10 in each process of designing the aspherical design single-sided progressive addition lens 10 according to the present invention. In FIG. 5, parts corresponding to those in FIG. The corresponding points on the lens rear surface of the distance measurement reference point P1 and the near vision design reference point P2 in the state of FIG. 5A are indicated as P1a and P2a, respectively, and the distance measurement reference point P1 in the state of FIG. Corresponding points on the lens rear surface 2 of the near portion design reference point P2 and the prism measurement reference point P3 are respectively shown as P1b, P2b, and P3b. In addition, corresponding points on the lens rear surface 2 of the distance measurement reference point P1, the near vision design reference point P2, and the prism measurement reference point P3 in the state of FIG. 5C are respectively shown as P1 ′, P2 ′, and P3 ′. . Here, the corresponding point on the lens rear surface is an intersection of the normal line at each point (P1, P2, P3) on the lens front surface 1 and the lens rear surface 2. Note that the corresponding points (P1a, P2a, P1b, P2b, P3b, P1 ′, P2 ′, P3 ′) are intersection points between the normal of the lens rear surface 2 passing through the points (P1, P2, P3) and the lens rear surface 2. Or a position of an intersection of a line parallel to the Z axis passing through each point (P1, P2, P3) and the rear surface 2 of the lens.

FIG. 5A shows a state before the lens rear surface 2 that is the aspheric design surface is moved downward relative to the lens front surface 1 that is the progressive surface as in FIG. 2 described above. In this state, the aspheric design surface reference point Ph is located on the normal line passing through the prism measurement reference point P3 on the lens front surface 1.
Further, the rear surface 2 of the lens is disposed at a distance from the front surface 1 so that the center thickness of the lens 10 becomes a predetermined value.
In this example, since the refractive power of the prism is 0, the normal direction Np of the lens front surface 1 at the prism measurement reference point P3 and the normal direction Nph of the lens rear surface 2 at the reference point Ph of the aspheric design surface are obtained. Match. When designing a lens having prism refractive power, the lens rear surface 2 is tilted so that the prism refractive power can be obtained.

Next, the lens rear surface 2 is shifted downward relative to the lens front surface 1. As described with reference to FIG. 3, the surface refractive power and the near portion design at the corresponding point P1 ′ on the rear surface of the distance measurement reference point are described. While changing the orientation of the rear surface 2 so that the difference from the surface refractive power at the corresponding point P2 ′ on the rear surface of the reference point is within a predetermined range, preferably approximately the same, and the refractive power of the prism is as designed, Move. At this time, it is more preferable that the lens center thickness is set to a predetermined value.

The state after this movement is shown in FIG. 5B. In the example of FIG. 5B, the normal direction Npb of the point P3b on the rear surface of the lens corresponding to the prism measurement point P3 is the normal direction of the lens front surface of the prism measurement reference point P3 so that the prism refractive power becomes zero. Match. Further, the aspheric design surface reference point Ph is located below the prism measurement reference point P3 or the rear surface corresponding point P3b in the Y-axis direction on the YZ plane, and the near portion design reference point P2 or the subsequent point. It is located above the corresponding point P2b on the surface in the Y-axis direction. The normal direction of the lens rear surface of the aspheric design surface reference point Ph is inclined downward on the YZ plane on the side facing the lens front surface. In FIG. 5B and later-described FIG. 5C, the lens rear surface 2 in the previous state in FIG.
The position where the lens rear surface 2 is shifted downward relative to the lens front surface 1 is substantially the middle position in the Y-axis direction between the distance measurement reference point P1 and the near vision design reference point P2, and the corresponding correspondences. The calculation can be simplified by moving the aspherical design surface reference point Ph to a position approximately in the middle of the point (P1a, P2a) in the Y-axis direction.

Next, in the state of FIG. 5B, the distance portion refractive power when it is assumed that the distance portion refractive power is measured using a lens meter according to the method described in JIS is calculated, and the prescription power and The shape of the lens rear surface 2 is deformed so as to remove the above error from the entire lens rear surface. If the refractive power of the prism does not match the design value after the deformation, the direction of the rear surface 2 is further changed so as to meet the design value or fall within the allowable range.
Further, when the center thickness of the lens 10 (usually, the thickness at the prism measurement reference point P3) is not a predetermined value, the rear surface 2 is parallel to the Z-axis direction so as to be within a predetermined value or an allowable range thereof. Move. FIG. 5C shows the state of the rear surface 2 after the direction change or parallel movement. Since the amount of deviation of the refractive power of the prism 2 and the amount of deviation of the center thickness after deformation of the shape of the rear surface 2 are usually very small, the processing for changing the direction of the rear surface 2 and the processing for translation are not performed. It may be performed only when the center thickness is not within the allowable range.

  5A to 5C, the shape, orientation, and position of the lens rear surface 2 made of an aspheric design surface with respect to the lens front surface 1 made of a progressive surface selected based on the power of prescription are calculated. The final completed shape of the refractive power lens is determined. The aspherical design single-sided progressive addition lens 10 thus designed has the surface refractive power at the corresponding point P1 ′ on the rear surface of the distance measurement reference point and the surface refraction at the corresponding point P2 ′ on the rear surface of the near reference point. There can be no difference from the force or within a predetermined range, the prism refractive power can be within a design value or an allowable range thereof, and the center thickness can be within a predetermined value or an allowable range thereof.

  In FIGS. 5A to 5C described above, the shape and direction of the lens and changes thereof are exaggerated for easy understanding.

Next, based on FIG. 12, an embodiment according to the shape data creation device for the progressive power lens of the present invention will be described.
FIG. 12 is a block diagram corresponding to the flowcharts shown in FIGS. 9 to 11 to be described later, and shows the functions of the design calculation computer as blocks. As shown in FIG. 12, a progressive-power lens shape data creation device 100 according to an embodiment of the present invention includes a design calculation computer 110 to which an input device 101 and an output device 102 are connected, and a data server 150. Composed.

As shown in FIG. 12, the data server 150 includes a storage unit 151. The storage unit 151 includes an order database 153 in which order data from a user is accumulated, and lens shape data designed by the design calculation computer 110. Is stored in the design database 152.
Further, various data necessary for calculation processing by the design calculation computer 110 may be stored.
On the other hand, the design calculation computer 110 is a computer for taking in data necessary for design from the data server 150 and designing a progressive addition lens based on an installed program, and includes a processing unit 120 and a storage unit 140. ing. The processing unit 120 is described as means for realizing each function when the program is activated.

  The storage unit 140 also stores data necessary for lens design (for example, lens front surface (progressive surface) shape data 143), and lens shape data (for example, spherical design lens shape data 142 and non-standard data) designed by the processing unit 120. Spherical design lens shape data 141) is stored. Details of each function of the processing unit 120 will be described later. The various functions and devices of the lens shape data creation device 100 may be integrated and dispersed as appropriate.

Next, based on the flowcharts of FIGS. 9 to 11 and the block configuration diagram of FIG. 12, an example of a method for creating the shape data of the progressive-power lens according to the embodiment of the present invention will be described.
First, data necessary for shape design of the progressive power lens is acquired from the storage unit 151 of the data server (step S1).
Here, data necessary for lens design includes prescription data, spectacle lens information, layout information, and the like. The prescription data includes spherical power, astigmatism power, astigmatism axis, prescription prism power, prism base direction, addition power, and the like. The spectacle lens information includes the lens material, the refractive index, the type of optical design on the front and back surfaces of the lens, the lens center thickness, the outer diameter of the uncut lens, and the prism thinning. The layout information includes interpupillary distance, near pupil distance, eye point position, progressive zone length, and the like. These data are stored in advance as order data 153 in the storage unit 151 of the data server 150 based on the order contents from the customer.

  Next, the shape of the front surface (progressive surface) 1 of the lens is designed based on the data acquired in step S1 (step S2, front surface shape design processing 134). This design process may be performed each time, or shape data created in advance may be used. For example, progressive surface shape data corresponding to the prescription frequency is created in advance for each optical design type and stored as the progressive surface shape data 143 in the storage unit 140, and is appropriate according to the optical design type and the prescription frequency of the order contents. You may make it select the shape data of a progressive surface.

Subsequently, the aspherical surface is designed on the rear surface side of the lens, that is, the surface opposite to the progressive surface (steps S3 to S7).
First, shape data of the lens rear surface 2 composed of a spherical design surface (spherical surface or toroidal surface) that matches the target prescription power is designed, and the shape data of the lens rear surface 2 is arranged at a predetermined position with respect to the lens front surface 1. Then, the lens shape data is calculated (step S3, rear surface shape spherical design process 133).

  When the spherical design surface is a toroidal surface, the position of the lens rear surface 2 relative to the lens front surface 1 is such that the toroidal surface reference point of the lens rear surface is located on the normal line of the prism measurement reference point P3 of the lens front surface 1 and The direction and interval of the lens rear surface 2 with respect to the lens front surface 1 are set so that a predetermined center thickness and prism refractive power based on the above are obtained. When the spherical design surface is a spherical surface, a straight line connecting the center of the sphere including the spherical design surface and the corresponding point on the rear surface of the prism measurement reference point so as to obtain a predetermined center thickness and prism refractive power based on the contents of the order. The direction is set and the distance between the lens rear surface 2 and the lens front surface 1 is set.

  The lens shape data calculated here is a spherically designed single-sided progressive power lens. The shape data of the spherical design surface may be created in advance and stored in the storage unit 140, and may be selected according to the order contents or prescription. The lens shape data calculated in step 3 is stored in the storage unit 140 as lens shape data (hereinafter also referred to as spherical design lens shape data) 142 of the spherically designed single-sided progressive-power lens.

Next, the spherical design surface is modified so as to be aspherical or non-toroidal so as to reduce various aberrations of the spherically designed single-sided progressive addition lens designed in step S3. This process is a loop process from step S4 to step S7.
First, the transmittance distribution on the reference sphere is calculated for the spherical design lens shape data designed in step S3 (step S4, transmittance distribution calculation processing 129).

Then, a deviation amount from the ideal distribution (ideal distribution calculation processing 131) of the transmission number calculated in advance according to the order contents is calculated with respect to the calculated transmission number (step S5, deviation amount calculation determination processing 130). ).
Further, it is determined whether or not the deviation amount is within a predetermined value range (step S6, deviation amount calculation determination processing 130). If the deviation amount is not within the predetermined range, this deviation amount is calculated based on the deviation amount of this frequency. The shape of the lens rear surface 2 is deformed and corrected so as to reduce the amount of deviation (step S7, rear surface aspherical design process 132). The determination as to whether or not the amount of deviation is within a predetermined range may be made by, for example, calculating the amount of deviation at each point of the distribution and determining whether or not the total value is within the predetermined range. The shape of the rear surface of the lens corrected in step S7 is an aspheric design surface. Then, based on the lens shape having the corrected aspheric design surface, the process returns to step S4 in order to calculate the transmittance distribution on the reference spherical surface again.

  When the amount of deviation is within a predetermined range by repeating steps S4 to S7 (YES in step S6), the shape data is stored in the storage unit 140 as lens shape data (hereinafter, non-spherical design single-sided progressive addition lens). 141 (also referred to as spherical design lens shape data). Then, the process proceeds to the next step (A) shown in FIG.

First, as shown in FIG. 10, the calculated spherical design lens shape data 142 and aspherical design lens shape data 141 are used for distance measurement of the lens front surface 1 to a lens meter according to the addition power measurement method defined by JIS. Aspherical design lens shape with respect to the addition power ADD _{S in} the case of spherical design lens shape data 142 is calculated by calculating the addition refractive power when it is assumed that the measurement is performed by applying the measurement reference point P1 and the near design reference point P2. _A deviation amount (| ADD _A -ADD _S |) of the addition refractive power ADD _{A in} the case of the data 141 is calculated (step S8, addition power calculation / deviation amount determination processing 127).

Then, an appropriate threshold value Dt1 (for example, a small value such as 0 or 0.01) is set, and whether or not the amount of addition power deviation | ADD _A −ADD _S | is equal to or less than the threshold value Dt1, that is,
｜ ADD _A −ADD _S | ≦ Dt1
(When Dt1 is set to 0, | ADD _A -ADD _S | = 0)
(Step S9, power addition calculation / deviation amount determination processing 127).

If it is determined in this step S9 that | ADD _A -ADD _S |> Dt1 (NO in step S9), the lens rear surface 2 is vertically lowered (Y-axis direction) while keeping the prism refractive power unchanged. The aspherical design surface reference point Ph is moved downward relative to the lens front surface 1 (step S10, rear surface downward movement processing 128).
Then, the lens shape after the movement is newly stored in the storage unit 140 as aspherical design lens shape data 141. Thereafter, based on the aspherical design lens shape 141 after movement, the amount of deviation of the addition refractive power is calculated again, and steps S8 to S10 are repeated until it becomes equal to or less than the threshold value Dt1.

  In steps S8 to S10, when the deviation amount of the addition power finally becomes equal to or less than the threshold value Dt1 (YES in step S9), the obtained aspheric design lens shape data 141 and the spherical design lens shape are obtained. It is assumed that the data 142 is measured when the lens rear surface 2 is measured by applying the lens rear surface 2 to the lens meter so that the optical axis thereof overlaps the distance measurement point in accordance with the measurement method of the distance measurement refracting power defined by JIS. The refracting part power is calculated, and the distance of the distance refracting power in the case of the aspherical design lens shape data 141 with respect to the case of the spherical design lens shape data 142 is calculated (step S11, distance power calculation / displacement determination) Process 125).

Here, the amount of deviation of the distance portion refractive power (spherical refractive power deviation amount S _E , astigmatic refractive power deviation amount C _E , astigmatic axis deviation amount Ax _E ) is specifically the distance design portion of the spherical design lens shape. Refractive power (spherical refractive power S _S , astigmatic surface refractive power C _S , astigmatic axis Ax _S ), and distance-use refractive power (spherical refractive power S _A , astigmatic surface refractive power C _A) , astigmatic axis of aspherical design lens shape is calculated from the difference between Ax _a).

Then, appropriate threshold values (spherical refractive power threshold St, astigmatic refractive power threshold Ct, astigmatic axis threshold Axt) are set, and whether or not the amount of deviation of the distance portion refractive power is equal to or smaller than the threshold,
| S _E | ≦ St
| C _E | ≦ Ct
| Ax _E | ≦ Axt
(Step 12, distance power calculation / deviation amount determination processing 125).

  If the amount of deviation exceeds the threshold (NO in step S12), the shape of the rear surface of the lens is deformed so that the amount of deviation is subtracted from the entire lens (step S13, rear surface shape modification process 126). The obtained lens shape is newly stored in the storage unit 140 as aspherical design lens shape data 141. Then, the process proceeds to the next step (B) shown in FIG. Similarly, when it is determined in step S12 that the deviation amount is equal to or smaller than the threshold value, the process proceeds to the next step (B).

  Next, as shown in FIG. 11, with respect to the obtained aspherical design lens shape data 141, the lens rear surface 2 is a lens meter and its optical axis is a prism measurement reference point according to the prism refractive power measurement method defined in JIS. The prism refractive power when it is assumed that the measurement is performed so as to overlap with P3 is calculated, and a difference ΔDp with respect to the target predetermined prism refractive power is calculated (step S14, prism power calculation / deviation amount determination processing 123). Then, it is determined whether or not the difference ΔDp is equal to or smaller than a predetermined threshold value Dt2 (step S15, prism power calculation / deviation amount determination processing 123). If the difference ΔDp is not less than or equal to the threshold value (NO in step S15), the direction of the lens rear surface is changed so as to change the normal direction of the position corresponding to the prism measurement reference point on the lens rear surface (step S16, rear surface). The direction changing process 124) is performed so that the predetermined prism refractive power is obtained, and the process proceeds to the next step S17.

  If it is determined in step S15 that the difference ΔDp is equal to or smaller than the predetermined threshold value Dt2 (YES in step S15), the process proceeds to the next step S17. After step S15 or step S16, the obtained lens shape is newly stored in the storage unit 140 as lens shape data 141 of aspherical design.

  Then, the lens center thickness (lens geometric center thickness or lens thickness at the prism measurement reference point) is calculated for the aspheric design lens shape data 141 obtained in the previous step (lens center thickness calculation processing). 121) The lens rear surface 2 is translated in the normal direction at the prism measurement reference point of the lens front surface 1 so as to be a predetermined value when not within the predetermined value tolerance (step S17, rear surface width direction moving process). 122), the obtained lens shape data is newly stored in the storage unit 140 as aspherical design lens shape data 141. The aspheric design lens shape data 141 is sent to the data server 150 and stored as design data 152 in the storage unit 151. This completes the data forming process of the progressive power lens.

  Based on the lens shape data 141 (design data 152) determined through the above calculation processing steps, the progressive addition lens of the configuration of the present invention is manufactured.

  The progressive power lens designed in this way has an aspherical surface or a non-toroidal surface on the side opposite to the progressive surface in order to improve the visual acuity on the lens peripheral side. The amount of deviation from the prescription power of the distance power and the addition power when measured with a lens meter can be suppressed within a desired range or according to the prescription power. Therefore, it is possible to reliably suppress the distance portion refractive power, the addition refractive power, and the like within a tolerance for the display value determined by JIS.

  As described above, as the progressive-power lens shape data creation apparatus according to the present invention, the functions of the processing unit 120 of the computer are described. The actions or functions of these means are all realized by a program installed in the computer, and the essential part of the above-described apparatus is the function of the computer program. Therefore, the present invention can realize the above-described function as a program for designing shape data of a progressive power lens in which one surface is formed of a progressive surface and the other surface is formed of an aspherical surface or a non-toroidal surface. is there.

  It should be noted that the present invention is not limited to the configuration described in the above embodiment, and includes various modifications and application examples without departing from the gist of the present invention described in the claims. .

Next, an example of a progressive power lens having a shape designed in this way will be described together with a comparative example to which the present invention is not applied.
First, the lens of the comparative example will be described.
The first comparative example is an example of a conventional spherically designed single-sided progressive power lens in which the front surface of the lens is a progressive surface and the rear surface of the lens is a spherical surface. As for the prescription power of the lens of Comparative Example 1, the distance-part refractive power is spherical refractive power: 6.00D, astigmatic refractive power: 0.00D, and the addition refractive power is 2.00D. The prism refractive power is 0.00Δ. The curve on the front surface of the lens is 7.00D, and the curve on the rear surface of the lens is 4.19D. The refractive index of the lens material is 1.60, and the center thickness is 6 mm.
17A to 17C show surface astigmatism, surface average power, and height distribution of the lens front surface (progressive surface) of the lens of Comparative Example 1. 17D to 17F show surface astigmatism, surface average power, and height distribution on the rear surface (spherical surface) of the lens. FIGS. 17G and 17H show astigmatism and power error (average power of error with respect to the prescription power in the distance portion) as the power on the reference spherical surface.

The second comparative example is an example of a conventional spherically designed single-sided progressive power lens in which the front surface of the lens is a progressive surface and the rear surface of the lens is a toroidal surface. The lens of Comparative Example 2 has a prescription power of a distance portion refractive power of 6.00D for spherical power, -3.00D for astigmatic power: -3.00D, an astigmatic axis: 0 °, and an addition power of 2.00D. It is. The prism refractive power is 0.00Δ. The front lens curve is 7.00D, the rear lens curve is 4.19D at the maximum, and 1.19D at the minimum. The refractive index of the lens material is 1.60, and the center thickness is 6 mm.
18A to 18C show surface astigmatism, surface average power, and height distribution of the lens front surface (progressive surface) of the lens of Comparative Example 2. 18D to 18F show surface astigmatism, surface average power, and height distribution on the rear surface (toroidal surface) of the lens. Also, astigmatism and power error as transmittance on the reference spherical surface are shown in FIGS.

Next, the lens of the example will be described.
The first embodiment is an example of an aspherical design single-sided progressive power lens according to the present invention in which the front surface of the lens is a progressive surface and the rear surface of the lens is an aspherical surface. As for the prescription power of the lens of Example 1, the distance power is spherical power: 6.00D, astigmatic power: 0.00D, and the addition power is 2.00D. The prism refractive power is 0.00Δ. The curve on the front surface of the lens is 7.00D, and the curve on the rear surface of the lens is 4.19D. The refractive index of the lens material is 1.60, and the center thickness is 6 mm.
The surface astigmatism, surface average power, and height distribution of the lens front surface (progressive surface) of the lens of Example 1 are shown in FIGS. Also, surface astigmatism, surface average power, and height distribution of the rear surface (aspheric surface) of the lens are shown in FIGS. Also, astigmatism and power error as transmittance on the reference spherical surface are shown in FIGS.

The second embodiment is an example of an aspherical design single-sided progressive power lens in which the front surface of the lens is a progressive surface and the rear surface of the lens is a non-toroidal surface. The lens of Example 2 has a prescription power of a distance portion refractive power of spherical refractive power: 6.00 D, astigmatic refractive power: −3.00 D, astigmatic axis: 0 °, and addition refractive power of 2.00 D. It is. The prism refractive power is 0.00Δ. The front lens curve is 7.00D, the rear lens curve is 4.19D at the maximum, and 1.19D at the minimum. The refractive index of the lens material is 1.60, and the center thickness is 6 mm.
The surface astigmatism, surface average power, and height distribution of the lens front surface (progressive surface) of the lens of Example 2 are shown in FIGS. 7D to 7F show surface astigmatism, surface average power, and height distribution on the rear surface (non-toroidal surface) of the lens. Also, astigmatism and power error as transmittance on the reference spherical surface are shown in FIGS.

Here, FIGS. 6A to C, G, H, FIGS. 7A to C, G, H, FIGS. 17A to C, G, H, FIGS. 18A to C, G, H, and FIGS. 8A and 8B described later. The coordinates are set such that the prism measurement reference point P3 is the origin, the horizontal direction of the lens passing through the prism measurement reference point P3 and perpendicular to the normal of the lens front surface 1 at the prism measurement reference point P3 is the X axis, and the lens perpendicular to the normal The vertical direction of Y is the Y axis. The coordinates shown in FIGS. 6D to F, FIGS. 7D to F, FIGS. 17D to F, and FIGS. 18D to F are based on the corresponding points P3 ′, P3 ″, and P3 ′ ″ on the rear surface of the prism measurement reference point. Through the corresponding points P3 ′, P3 ″, P3 ′ ″ on the rear surface of the prism measurement reference point, and the lens rear surface 2 at the corresponding points P3 ′, P3 ″, P3 ′ ″ on the rear surface of the prism measurement reference point, The horizontal direction of the lens perpendicular to the normal lines 22 and 32 is the x-axis, and the vertical direction of the lens perpendicular to the normal line is the y-axis. 6C, FIG. 7C, FIG. 17C, and FIG. 18C, the height is the height from the XY plane to the lens front surface, and in FIGS. 6F, 7F, 17F, and 18F, the height is x− The height from the y plane to the rear surface of the lens.
The shapes of the lens front surfaces (progressive surfaces) of Comparative Examples 1 and 2 and Examples 1 and 2 are all the same.

  As a result of measuring the distance portion refractive power and the addition refractive power using the lens meter according to JIS T7315 for the lenses of Comparative Examples 1 and 2 and Examples 1 and 2, the comparative example shows almost no error with respect to the prescription power. It was. The errors with respect to the prescription power in Example 1 were as follows: the distance power was -0.05D for spherical power, -0.04D for astigmatic power: -0.04D, and -0.03D was added power. Further, the error with respect to the prescription power in Example 2 is that the distance power is spherical power: 0.00D, the astigmatic power: 0.00D, the astigmatic axis: 0 °, and the addition power is -0.03D. Met.

  As described above, the distance portion refractive power and the addition refractive power measured by the lens meters of the lenses of Examples 1 and 2 are within the allowable error defined in JIS T7315. Therefore, it is understood that there is no need to separately display the check frequency.

  FIGS. 6A to C, FIGS. 7A to C, FIGS. 17A to C, and FIGS. 18A to C are lens front surfaces (progressive surfaces) formed based on the same design data. The surface average frequency and height distribution are shown. In FIGS. 17D and E and FIGS. 18D and 18E, since the surface is a spherical design surface, a substantially constant value is shown over the entire area of the rear surface of the lens, but in FIGS. 6D and E and FIGS. 7D and E, Since this is an aspheric design surface to which the present invention is applied, an influence due to the aspherical surface is seen on the lens peripheral side, and a slight influence due to the aspherical design surface reference point moving downward is seen.

FIGS. 8A and 8B show astigmatism and power error as the transmittance on the reference spherical surface of the target performance in the examples of FIGS. 17 and 6 and the examples of FIGS.
6G and H and FIGS. 7G and H of the lens having the aspherical design on the rear surface of the lens according to the present invention are shown in FIGS. 17G and 17G and FIGS. 18G and H of the lens having the spherical design on the rear surface of the comparative example. It can be seen that it is closer to the target performance compared to the transmission number. Therefore, it can be seen that the aberration correction is sufficiently performed in these examples.

1, 2, 31 ... Lens front surface (progressive surface), 2, 22 ... Lens rear surface (aspheric design surface), 32 ... Lens rear surface (spherical design surface), 10, 20, 30 ... Progressive power lens, 100 ... Progressive power lens shape data creation device, 110 ... Design calculation computer, 120 ... Processing unit, 150 ... Data server, P1 ... Distance measurement unit Point (front side), P1 ′, P1 ″, P1 ′ ″ ... corresponding point on the rear side of the distance measurement reference point, P2 ... Near part design reference point (front side), P2 ′, P2 ”, P2 ′ ″ — corresponding point on the rear surface of the near reference design point, P3—prism measurement reference point (front side), P3 ′, P3 ″, P3 ′ ″ — prism measurement Corresponding point on the rear surface of the reference point, Ph: Aspheric design surface reference point

Claims (5)

In a progressive-power lens having a progressive surface and an aspheric design surface composed of an aspherical surface or a non-toroidal surface,
The reference point of the aspheric design surface is a position below the prism measurement reference point of the progressive surface in the vertical direction of the lens, and is a position above the near-field design reference point,
A difference in surface power at a position on the aspheric design surface corresponding to a distance measurement reference point of the progressive surface with respect to a surface power at the reference point of the aspheric design surface;
Wherein a difference in surface refractive power at a position on the aspheric design surface corresponding to the near design reference point of the progressive surface relative to the surface refractive power at the reference point of the aspherically designed surface is equal properly, the progressive-power lens. The reference point of the aspheric design surface is located approximately at the center in the vertical direction of the lens between the distance measurement reference point and the near design reference point on the progressive surface.
The progressive-power lens according to claim 1. The distance power and addition power of the lens measured by a lens meter are within the tolerance of distance power and addition power as the prescription power of the lens.
The progressive-power lens of Claim 1 or 2. The reference point of the aspheric design surface and the prism measurement reference point are located on a vertical plane including the normal of the lens front surface at the prism measurement reference point.
The progressive-power lens in any one of Claims 1-3. The reference point of the aspheric design surface is located on a vertical plane including the distance measurement reference point and the near design reference point and parallel to the normal of the lens front surface at the prism measurement reference point. Item 4. A progressive power lens according to any one of Items 1 to 3.

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